Citation

Geoscience Australia provides most of its products for free under a Creative Commons Attribution 4.0 International Licence. We only require that you reference the use of our data or information using the following citation:
Drummond, B.J., 1979. A crustal profile across the Archaean Pilbara and northern Yilgarn cratons, northwest Australia. BMR Journal of Australian Geology and Geophysics  4:3:171-180. Bureau of Mineral Resources, Geology and Geophysics, Canberra.

Abstract

Two Archaean cratons are exposed in the Precambrian shield of Western Australia: the Pilbara in the north and the Yilgarn in the south. They are separated by the Capricorn Orogen. Seismic recordings of quarry blasts in the north of the West Australian shield indicate that the upper crustal rocks have seismic velocities of 6.0 km s^-1, and are probably of acid to intermediate chemical composition. They overlie a lower crust, presumed to be granulitic, which has a seismic velocity of 6.4 km s^-1 at 13 km depth in the north of the Pilbara Craton and 16 km in the north of the Yilgarn Craton. The northern Yilgarn has a third layer, with a seismic velocity of about 7.0 km s^-1, at the base of the crust. This may represent a higher grade (eclogite?) phase, or it may indicate injection of basic material into the base of the crust. The crust-mantle boundary at the base of the Pilbara Craton and Capricorn Orogen appears to be transitional - it shows velocity gradients rather than a first-order velocity discontinuity. Within the Pilbara Craton, the crust is about 28 km thick in the north and 33 km in the south. South of the Pilbara Craton, the crust thickens under the Capricorn Orogenic Belt, and again under the northern Yilgarn Craton where it is 52 km thick. The form of the structures in the zone of thickening cannot be determined uniquely from the present data. Three models incorporating faults or monoclines and a wedge of 7.0 km s^-1 material at the base of the crust have been derived. The different crustal thicknesses of the cratons suggest that they formed separately and were then tilted towards the Orogenic Belt.
Google map showing geographic bounding box with values North bound -20.0 East bound 121.0 West bound 115.0 South bound -27.0
Downloads
For information on acquiring this product,
please contact Geoscience Australia Client Services via:

fax:
+61 2 6249 9960; or
phone:
1800 800 173 (within Australia);
 
+61 2 6249 9966 (outside Australia).

Product Type/Sub Type

nonGeographicDataset - GA Publication - Journal

Constraints

license
Creative Commons Attribution 4.0 International Licence

IP Owner

Commonwealth of Australia (Geoscience Australia)

Author(s)

Date (publication)

1979

Product Type

nonGeographicDataset

Topic Category

geoscientificInformation

Keywords

GA Publication
Journal
Earth Sciences

Resource Language

English

Resource Character Set

utf8

Resource Security Classification

unclassified

Geographic Extent

North bound
-20.0
East bound
121.0
West bound
115.0
South bound
-27.0

Lineage

Unknown

Digital Transfer Options

onLine

DISTRIBUTION Format

pdf

Distributor

Role
distributor
Organisation Name
Geoscience Australia
City
Canberra
Administrative Area
ACT
Postal Code
2601
Country
Australia
Email Address

Metadata File Identifier

fae9173a-6fc5-71e4-e044-00144fdd4fa6

Metadata Standard Name

ANZLIC Metadata Profile: An Australian/New Zealand Profile of AS/NZS ISO 19115:2005, Geographic information - Metadata

Metadata Standard Version

1.1

Metadata Date Stamp

2015-05-19

METADATA SECURITY CLASSIFICATION

unclassified

Metadata Contact

Role
pointOfContact
Organisation Name
Geoscience Australia
City
Canberra
Administrative Area
ACT
Postal Code
2601
Country
Australia
Email Address
Downloads
For information on acquiring this product,
please contact Geoscience Australia Client Services via:

fax:
+61 2 6249 9960; or
phone:
1800 800 173 (within Australia);
 
+61 2 6249 9966 (outside Australia).